Perfluoroalkanesulfonic acids are employed as wetting agents or as surfactants in detergents. They also find utility in the preparation of products having interfacial properties.
The preparation of these compounds by electrofluorination (for example, according to U.S. Pat. No. 2,732,398) is known. A preparation process employing an electrochemical method is ruled out, however, because of its excessively high industrial cost.
Known chemical methods of preparation of these compounds involve the condensation of sulfur dioxide with perfluoroalkylmagnesium derivatives or with perfluoroalkyl halides in the presence of zinc (U.S. Pat. No. 4,221,734). From an industrial safety standpoint, such magnesium-containing derivatives, being far too violent, cannot be used.
Zinc, moreover, disadvantageously gives rise to zinc hydroxide when the reaction medium is treated. The separation of zinc hydroxide on an industrial scale presents serious problems.